This invention relates to photographic systems and more particularly, it concerns apparatus for accommodating modified format sizes of photographic sheet film in existing camera systems.
In the camera system marketed by Polaroid Corporation under the trademarks "Polaroid SX-70 Land Camera" and "Polaroid SX-70 Land Film", camera structure and operation are integrated with a container or pack of film in the sense that electric power for camera operation is supplied by a battery packaged with each film pack, a main power switch is closed upon full insertion of the film pack to connect the battery with camera carried electric circuitry, and the film container defines the location and to some extend the format area of an image to be formed on the uppermost of successive film sheet assemblies in the container. Each film sheet assembly in the system carries a supply of processing fluid in an amount calibrated to cover the image format area after exposure and passage of the sheet assembly between a motor driven processing roller pair supported in the camera. In particular, the processing fluid is spread across the interface between a pair of plastic sheets in each assembly, at least one of which plastic sheets is transparent for exposure of a light sensitive layer carried between the sheets and so that the resulting positive photographic image may be viewed.
Because of the construction of each film sheet assembly, its exterior appearance is that of a framed photograph in which four marginal edges are defined by paper or other similar material folded about these edges to secure the two plastic sheets in overlying coextensive relationship. The bottom marginal edge of the framed photograph is wide relative to the marginal side and top edges principally because it encloses the pod or supply of processing fluid carried by each film sheet assembly. Also, because of the construction of the sheet assemblies, the top wall of the container in which the film sheets are contained is provided with marginal lips dimensioned to substantially cover the framing margins of the photographic sheet including the bottom marginal edge in which the processing fluid pod is located.
In the operation of the system, the uppermost film sheet assembly in the container is exposed and then engaged at its rear edge (the top edge of the photograph) by a linearly driven pick and advanced through a slot in the front wall of the container for a distance calibrated to place the leading edge of the exposed film sheet (the bottom edge of the photograph) within the nip of the processing roller pair. The rollers then feed the exposed sheet assembly forwardly to first rupture the processing fluid pod, spread the processing fluid across the interface between the plastic sheets and finally discharge the exposed and processed sheet from the camera.
The outside dimensions of the presently available "Polaroid SX-70 Land Film" unit are approximately 89.times.108 mm to provide a substantially square image area approximately 79 mm on the side. The width of the framing margin at the bottom of the photograph is approximately 19 mm whereas the framing margins at the side and top edges of the photograph are approximately 5 mm. While the dimensions of the photograph are well suited for storage in albums or the like, versatility of such systems would be enhanced significantly by a capability of providing smaller format photographs, such as for example a 45 mm format to provide a "wallet-size" photograph or a photographic positive of a 35 mm format. The problems associated with adapting the existing system to such smaller format photographs entail not only one of positioning the smaller sized format film sheets properly within the existing film well of the camera but also an accommodation to the smaller format photograph of camera carried components such as the camera viewing system, the pick by which each film sheet is advanced from the container to the processing rollers, the power switch closed by full insertion of the film pack and the attainment of a smaller format photograph in which the marginally framed portions thereof, particularly the bottom marginal edge may both contain a supply of processing fluid and be properly proportioned aesthetically to the reduced image area.